Sewing machine shuttle



March 19, 1946. w. F. sHlMEK 2,396,755

SEWING MACHINE SHUTTLE I Filed sept. 2o, 1944` Patented Mar. 19, 1946 2,396,175.75 SEWING li/iACHINlll SHUTTLE William F. Shimek, Milwaukea'wisn., assignorlto United Shoe Machinery COFDQra ton, N. JL, a corporation o f erase Application September 20, 1944, Serial Np. 555%868 cilerfa 8 Claims.

The present invention relates to wax thread sewing machine shuttles and, more particularly, to improvements in constructions and arrangements of rparts for locking a thread supply case within the shuttle of a sewing machine 'and for imparting a tension to the shuttle thread while being withdrawn. from a thread case in the shuttle during sewing.

Inl a sewing machine shuttle such as that disclosed in United States Letters Patent No. 1,905,032, granted April 25, 1933, upon an application led in the name of Fred Ashworth, a thread supply,` case is provided having va locking slide movable diametrically across the end of the thread case to lock the thread case in position within the shuttle. To impart suitable tension to the shuttle thread and to lead the thread from the thread'case, in the patented shuttle, the thread case has a hollow stud projectingv inwardly to form a support fora supply cop inserted in thethread case and a hollow springpressed plunger within the stud subjects the thread leading from`the cop through the stud to pressure at the point where it enters. This construction of the thread case locking and tensioning devices is effective and is advantageous in operation'so long as the plunger Aand its actuating spring do not cause an excessive amount of wax to be stripped from'the thread as it is drawn through the hollow stud. When wax stripped from the thread accumulates on the spring and tension plunger, it forms a solid cake which resists proper operationY of the parts and which is likely to cause thread breakage upon the presence of irregularities inV thickness ofthe thread. Furthermore, the"`thread case ylocking slide is held inlocking position'jin the patented shuttle, by a' second similar hollow locking plunger, also within the hollow stud, actuated toward locking position by ythe opposite end of the same spring which'presses the tension plunger against the 'thread "and, if the 'tension 'spring becomes cake'd with hardened'wax; Vitis impos sibleto'relase the"locking slide "toremov the thread'case from the shuttle.

"Ariobjectof"the'present' invention is to improve 'thehcoiistructio'n `of"a wax'thread sewing machine shuttleandA thread 'case'of the type diselosed'in th'abovegmentibned patent in Suche way 'that aecuimuatibn' of Hardened wax on the f thread tensionandlckingslide holding spring will VAbe avoided,VV and otherwise 'to 'improve and perfect themanner of operation of a wax thread sewing( niachine"`tili'zing such' a shuttle.

embodying th feature'shf the' present in- Sii vention in the illustrated shuttle, which is equipped with a removable thread supply holder forming a closure for the shuttle in the form of a casing, and having a hollow stud projecting into the shuttle casing to guide the thread to the outer side of the supply holder and a hollow plunger in the stud through which the thread leads from the supply in the holder, there is provided a spring inside the stud of the holder, shielded by the plunger from contact with the thread passingtherethrough thereby preventing accumulation of wax on the spring and main; taining the parts in effective operating condition at all times. In order to obtain these results, the locking slide holding and thread tension spring is coiled about the plunger rather than inside the plunger `as heretofore and located within a space between the plunger and the inner surface of the hollow stud. Since the thread passes through the plunger, there'is no possibility of wax, stripped from the thread, accumulating on the spring when'so located. In .the particular form illustrated, with the use of two plungers, one for imparting tension tothe thread, and the other for holding the locking slide in locking position, the two plungers comprise a pair of telescopin-g members between which the spring is compressed. r A

These and other objects and features of the invention will become apparent from the following vdescription taken in. connection with the accompanying drawing, in which Fig. 1 is a view in front elevation of a shuttle, illustrating somewhat diagrainmatically its relation to the needle and the work being operated upon in a machine'embodying the presentinvention; A 4

Fig. 2 is a detail front viewv of the thread holder, indicating the casing for the shuttle, the parts beng shown in unlocked positions;

lig.Y 3 is a detail sectional view of the shuttle and thread holder, taken in section` along the une 11i-111 of Fig'. 2;

Fig. 4 is a sectional plan view oithe shuttle 'e and 'thread holder, taken on the line I-V-IV of Fig. 1, illustrating the position of the shuttle with relation to the shuttle raceway, driver and loop spreader; and

Fig. 5 is a detail view ony an enlarged scale of the locking slide holder and tension device shown in Fig. 4.

The shuttle illustratedA in the accompanying drawing is intended to cooperate with other stitch forming devices such as a straight hook needle 2 and a loop'spreader 4 and consists of a disitension plunger I4 is arranged to be acted upon by a coil spring I6 tending to force the plunger against the rear Wall of the shuttle casing, the plunger I4 forming a central conducting passage or guide for the thread, opening at the forward end ofthe thread holder with the thread leadingV from the interior of the thread cop between the plunger and the rear wall of the shuttle casing as in the machine of the prior patent above referred to. To produce the required sewing tension on the thread, the spring I6 exerts a suitable pressure on the plunger to resist movement of the thread through the stud. Y In order to lock the thread case in position in the shuttle casing, the holder 8 is-provided with a radially projecting flange I8 fitting a slot in the circular side wall of the shuttle casing, and a diametrically movable slide 2B, retained within a4 guideway 22 in the Vfront wall of the supply holder, is 'readily movableltoward and from a vgroove 24 in the circular wallof the 'shuttle casing at the opposite side from the flange I8. To

-holdcthe :locking slide in locking position, a sec-l ond hollow plunger 26 is slidingly mounted in the hollow stud Id and is provided with a reduced end entering a hole 28 formed at the proper point in the slide 20. 1 The slide 2U1may lbe conveniently released byY inserting a suitable tool A.in the hole `28 to force'the plunger 26 rearwardly away'from the slide,'thereby allowing it to be moved into unlocking position.

In. the shuttle ,of the Ashworth ypatent above referred to; the thread may'come into direct contact'with the locking slide holding and tension producing spring lso that any excess wax on the thread may'become stripped off and accumulated in the space surrounding the coils of the spring, in 'suchY a way that, when itbecomes hardened, it will immobilize the spring, therebyrendering the tension ineffective and preventing release of the locking slide when it is desired to remove the thread supply holder. This difliculty is further complicated by lint or foreign materials scraped oi the thread within the stud to form a vreinforcing agent for the hardened wax already accumulated therein.

. To prevent the accumulation of wax and other materials on the locking slide holding and tension producing spring I6 of the present invention, the spring is shielded from contact with the thread passing through the stud I0 by the tension, plunger I4, and the locking slide holding plunger 25 is co'nstructed to telescope with the'tension plunger in such a way as to provide complete shielding of the spring and the space surrounding the coils of the spring from contact with the thread. The tension plunger I4 is formed with an external shoulder 30 against which one end of the spring I6 acts, and the locking slide plunger 215 has a similar shoulder-.32 against which the other end of the spring acts, these shoulders being flanged to fit slidingly within the stud I and to act as barriers against the entry of wax or other foreign materials into the'space occupied by the spring. The adjacent telescoping ends of the two plungers I4 and 25 areshaped `to fit closely one within the other,

4coidal shuttle casing 6, the rearward end of which thus preventing entry of foreign materials between the plungers. Inasmuch as the outer end of the tension plunger I4 is arranged to face in the direction in which the thread moves during sewing operations, there is no danger that the wax will be scraped off the thread by the inner end vof the smaller tension plunger which is exposed topcontact with the thread.

l By this construction not only are the lwax and foreign materials excluded from contact with the coils of the plunger actuating spring but also, when the spring andv plungers are properly lubricated, the shielded space between the plungers and the inside surface of the stud Ii] aids in retaining the lubricant in place so that an extremely durable and effective arrangement is provided. Furthermore, there is less possibility of wear and abrasion in the moving parts including the plungers and spring.

The nature and scope of the invention having .been indicated and the several features having been described, what is claimed is: i l

l. A shuttle for shoe sewing machines, comprising a hollow casing, a removable thread supply holder forming a closure for the shuttle casing and provided with a hollow stud projecting into the casing through which thethread passes to the outer side of the holder, -and a hollow plunger in the stud through which the thread leads from the supply in the holder, in combination with a .spring inside the stud shielded by the plunger from contact with the thread passing through the plunger for pressing the plunger yieldingly against the thread to impart a tension thereto.

2. A shuttle for shoe sewing machines, comprising a hollow casing, afremovable thread supply holder forming a closure for the shuttle casing and provided with a'hollow stud projectinginto the casing through which the thread passes to the outer side of the holder, and ahollow plunger'in the stud through which the thread lea-ds from the supply in the holder, in combination with .a plunger actuating spring coiled about theplunger within the space between the plunger and the inside of the stud to shield the spring fromcontact with the thread. f

3. A shuttle for shoe sewing machines, comprising a hollow casing, a removable thread supply holder forming a closure for the shuttle casing and provided with a hollow stud projecting into the casing through which the thread passes to the outer side of the holder, and a hollow plunger in the stud through which the thread leadsV from the supply in the holder, in combination with a plunger actuating spring coiled about the plunger within the space between the plunger and the inside of the stud to shield the spring from contact with the thread, and an external shoulder on the plunger inside the stud against which the spring acts to press the plunger against the thread.

4. A shuttle for shoe sewing machines, comprising a hollow casing, a removable thread supply holder forming a closure for the shuttle casing, and means for removably locking the thread `holder to the shuttle casing, comprising a locking slide at the end of the thread holder arranged to move across the end of the holder and to engage a groove in the shuttle casing,l a hollow stud through which the thread passes from the supply in theholder to the outer side thereof, and a hollow plunger in the stud, in combination with a spring inside the stud, shielded'by the plunger from contact with the thread passing through the stud, for pressing the plunger yieldingly against the slide to engage a hole in the slidevand lock the slide when the slide is in locking position.

5. A shuttle for shoe sewing machines, comprising a hollow casing, a removable thread supply holder forming a closure for the shuttle casing and provided with a hollow stud projecting into the casing through which the thread passes to the outer side of the holder, a hollow plunger in the stud through which the thread leads from the supply in the holder, and means for removspring for pressing said second-mentioned plunger frictionally against the thread engaging the inner surface of the shuttle casing and for pressing the rst-mentioned plunger against the locking slide to engage a hole in the slide and lock the slide in locking position.

6. A shuttle for shoe sewing machines, comprising a hollow casing, a removablethread supply holder forming a closure for the shuttle casing and provided with a hollow stud projecting into the casing through which the thread passes to the outer side of the holder, a hollow plunger in the stud through which the thread leads from the supply in the holder, and means for removably locking the thread holder to the shuttle casing, comprising a locking slide in the end of the thread holder arranged to move across the end of the holder and to engage a groove formed in the shuttle casing, in combination with a thread tension device including a second hollow plunger slidingly'mounted in the stud, telescoping with the first-mentioned plunger, and a spring surrounding said plungers in the space between them andthe inner surface of the stud,

sewing operations.

to press one plunger yieldingly against the thread and the other yieldingly against the slide,

7. A shuttle for shoe sewing machines, comprising a hollow casing, a removable thread supply holder forming a closure for the shuttle casing and provided with a hollow stud projecting into the casing through which the thread passes to the outer side of the holder, a hollow plunger in the stud through which the thread leads from the supply iny the holder, and means for removably locking the thread holder to the shuttle casing, comprising a locking slide in the end of the thread holder arranged to move across the end of the holder and to engage a groove formed in the shuttle casing, in combination with a thread tension device including a second hollow plunger slidingly mounted in the stud, telescoping with the first-mentioned plunger, a spring surrounding said plungers in the space between them and the inner surface of the stud, to press one ,plunger yieldngly against the thread and the other yieldingly against the slide, and external shoulders on the plungers inside the stud against which the spring acts.

8. A shuttle for shoe sewing machines, comprising a hollow casing, a removable thread supply holder forming a closure for the shuttle casing and provided with a hollow stud projecting into the casing through which the thread passes to the outer side of the holder, and a hollow plunger in the stud through which the thread leads from the supply in .the holder, in combination with a spring inside the stud shielded by the plunger from contact with the thread passing therethrough to impart a tension vto the thread, and a second plunger arranged in surrounding relation with the first-mentioned plunger, the construction being such that the outer exposed end of the first-mentioned plunger faces in the direction toward which the thread moves during WILLIAM F. SHIMEK. 

